Grid with graduation markings succeeding in nonequidistant spaces relative to each other

ABSTRACT

A grid with graduation-markings of equal width relative to each other and succeeding in nonequidistant spacings, wherein the graduation-markings define center lines which follow each other in distances corresponding with a cycle of n graduation markings. The cycle has a period length of UNITS AND WHEREIN EACH FULL NUMBERED MULTIPLE OF A UNIT OCCURS AS SPACING BETWEEN TWO GRADUATION MARKINGS EXACTLY K TIMES.

United States Patent inventors Appl. No. Filed Patented AsslgneePriority GRID WITH GRADUATION MARKINGS SUCCEEDING IN NONEQUIDISTANTSPACES Primary Examiner-John Kominski Assistant Examiner-V. LaFranchiAttorney-Ernest G. Montague ABSTRACT: A grid with graduation-markings ofequal width relative to each other and succeeding in nonequidistantspacings, wherein the graduation-markings define center lines whichfollow each other in distances corresponding with a cycle ofn graduationmarkings. The cycle has a period length of n(n1) T units and whereineach full numbered multiple ofa unit occurs as spacing between twograduation markings exactly k times.

RELATIVE TO EACH OTHER 6 Claims, 10 Drawing Figs.

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GRID WITH GRADUATION MARKINGS SUCCEEDING IN NONEQUIDISTANT SPACESRELATIVE TO EACH OTHER The present invention relates to a grid withgraduation markings succeeding in unequal or nonequidistant spacesrelative to each other in general, and to such graduations, which haveequal GlAs of the division markings.

Such graduations are known and disclosed, for instance, in

US. Pat. No. 2,406,299, dated Aug. 20, 1946. Such divisions orgraduations divisions adapted to deliver a signal during theirdisplacement relative to a second similar or complementary graduation.Such a signal has in the vicinity of a predetermined relative positionarrangement of the two divisions or graduations, namely in a preferredrange, an appreciably steeper variation of its value than in otherposition arrangements. Divisions or graduations of this type can becharacterized by the feature over what size of displacement paththepreferred range extends, how high the signal and its change,respectively, is arranged in the preferred range, how high these valuesare in the remaining range, and how large of a section of the twodivisions of graduations must cooperate together, in order to obtain thementioned values. This section is to be called below the sensing visualfield, following the special case of the optically perceptivegraduations. It is to be understoodthat it is desired to obtain apossibly high signal or a high signal variation already from a verysmall sensing visual field, in addition, however, to maintain, as muchas possible, constantly small the disturbance signal, that is the signaloutside of the preferred range, whereby mostly also the expansion of thementioned preferred range in relation to the remaining displacement pathshould be maintained as small as possible. The individual requirementscontradict each other to a great extent, for which reason the solutionsobtained until now did not bring about sufficient results for allapplications.

It is one object of the present invention to provide a grid withdivision markings succeeding in nonequidistant spaces, wherein thedrawbacks of the mentioned divisionsor graduations are avoided.

It is another object of the present invention to provide a grid withgraduation markings succeeding in nonequidistant spaces, which are basedon the surprising finding that it is possible to form cycles of ngraduation markings, which have the period length units, and in whicheach full numbered multiple of a unit appears as distance between twograduation markings exactly k times. The smallest distance between twograduation markings amounts to one unit and one can make wide, forinstance, in optically perceptive graduations, the ranges constitutingthe individual graduation markings and contrasting relative to theirsurroundings up to the width of a complete unit. In this case thegraduation markings engage each other with the distance I and at thispoint apparently a double or multiple as wide graduation marking iscreated.

With these and other objects in view which will become apparent in thefollowing detailed description, the present invention will be clearlyunderstood in connection with the accompanying drawings, in which:

FIGS. 1 and 2 are examples of cycles in accordance with the presentinvention;

FIG. 3 is an example of two superposed grids each corresponding to thecycle of FIG. 2 in a periodically repeating arrangement;

FIG. 4 is an example of two superposed grids each corresponding to thecycle of FIG. I in a nonperiodic arrangement;

FIGS. 5 and 6 are further examples ofcycles;

FIGS. 7 and 8 are examples of superposed grids corresponding to thecycles of FIGS. 5 and 6, respectively, each in a nonperiodicarrangement;

multiple part of part of a full cycle if n is the number of the divisionmarkings and k is frequency of the appearance of any selected interval.For the individualexamples n, k and the length of. the period P, aregiven below in form of tables, and furthermore the pairs of divisionmarkings which result in a predetermined interval. P means the number ofthe smallest units which a cycle contains. The period length P is givenin multiples of its smallest unit. The graduation markings are theslotlike elements illustrated in the figures. The symbols a and b appearwithin the same elements since they indicate two different markingswhich engage with their edges straight, so that they appear as singlemarkings of their double width. In this case, the graduation markingsengage each other with the distance 1 and at this point apparently adouble or multiple wide graduation marking is created.

FIG. 1:

Interval FIG. 2:

Interval The corresponding tables for the examples of FIGS. 5 and 6 arenot particularly stated in order to save space. It can be, however, alsosimply shown there that within a graduation all graduation intervalsappear at equal frequency.

In accordance with the present invention the division markings oflengthor circular-graduations are arranged such, that the centerline ofthe graduation markings succeed each other in distances, whichcorrespond with such cycle of n graduation markings, which has theperiod length of .units and in which each full numbered multiple of a.unit appears as distance between two graduation rnarkings exactly k.times. The entire graduation can comprise thereby afull numing point itcould be assumed, that this fraction comprises at least (P-l /2 unitsand contains more than 2n/3 graduation characteristics.

FIGS. 3 and 4 show such examples.

In FIG. 3 two superposed sliding graduations are shown in succeedingdisplacement steps. The centerlines of the graduation markings follow indistances to each other, which correspond with those of the cycle ofFIG. 2. The section shown in FIG. 3 comprises twice the period length,while the graduations themselves can project selectively far beyond thisshown section. The resulting signal curve is applied, along the rightimage edge of FIG. 3. Upon complete overlapping, the free openingamounts to 7 units per period, in the shown section 14 units, outside ofthe preferred range completely constant 3 units per period, in the shownsection, 6 units.

FIG. 4 shows one such example, in which only one section of a fullperiod is used. The section is taken from the cycle of FIG. 1. Onerecognizes, that the creating signal curve brings about outside of thepreferred range a not completely but approximately constant disturbancesignal level.

FIGS. 7 and 8 show further examples for graduations, which form asection of cyclic graduations of the art of the present invention. Therelative displacement of the graduations and the signal curve are shownonly at the edge of the Figures due to their great length. One caneasily convince oneself, that the signal curve does not increase anymore outside the shown range.

The following table reflects the characteristic values for thenonperiodic examples of FIGS. 1 and 4, FIGS. and 7, and FIGS. 6 and 8:

Nomination Soown in Section 11 m L mL n/m FIG. 6 .l 2 26 0. 346 4,5 FIG.5 l0 1 56 0.170 FIG. 1 6 1 18 0.333 6 L Length of the graduation (inmultiples ofa field width) n Number ofthe open fields m Maximum of thesignal curve outside of the preferred range (in multiples ofa fieldwidth) For the characterization of the individual graduations (compareFIG. 9).

L is determining for the dissolution capacity (the larger L, the smalleris the preferred range within which the steep fall of the signal fromthe top value n to no more the value In takes place, in comparison tothe length of the graduation).

n/L is determining for the transparency of the graduation, also for theabsolute height of the signal.

n/m is determining for the ratio usesignal/noise signal (signal to noiseratio) In FIG. 9 is shown in connection with the graduations T to Tmentioned as examples, how a quantitative evaluation of such graduationcan be performed. The graduations in accordance with the presentinvention are disposed in the space L, n/L and n/m on a curved face,which can be placed by the points T to T indicated by crosses. The areais, of course, not limited to the shown range and is particularlyselectively extendable in the direction of rising L. With thegraduations according to the present invention, equally valuedgraduations are disposed on the same face as the latter. Othergraduations, which are disposed below this area, must be characterizedas less good. The curve h/m== is drawn furthermore in FIG. 9, whichvalues of n/L and L with a single slot can be obtained (which of courseis part of the status of the prior art). For the individual slot a ration/m== can be obtained. The present invention aims to obtain with valuesof L and n/L. which deviate from the shown curve nlm=== to achieve asmuch as possible high values of-nlm, all. and L.

FIG. 10 shows a simple arrangement with which signals are produced uponrelative displacement of the graduations. The

graduation carriers and 101 made of transparent material are lighted bya device which comprises a lamp 103 and condenser I04. A lens 105collects the light on a phototransformer l06 which emits an electricalsignal to the conduit 107. Upon movement of the graduation carrier 100and 101 in the direction of the arrow 108, the desired signal isobtained by the cooperation of the graduation markings 109 and 109'(only shownschematically).

The graduations can, however, deviating from the example i of FIG. 10,also be sensed photoelectrically, for instance magnetically,capacitively or inductively.

Also a plain optically visual observation is possible. In this caseadvantageously periodic graduations are used. By the absolutely equalgray value between. the signal tops, a reading possibility very safe forthe eye results, when the narrow signal points find use as optical fineindicator or similar element.

The markings of the present invention may, for example, be

used in the device of U.S. Pat. No. 2,406,299 instead of the units andeach full numbered multiple ofa unit occurring as spacing between anytwo of said graduation markings exactly k times, n and k being integralnumbers satisfying the relationship 3 and 5 respectively.

2. The grid, as set forth in claim 1, wherein said individualgraduation-markings comprise ranges, contrasting relative to theirsurrounding, of a width at the most of one unit.

3. The grid, as set forth in claim 1, wherein the total graduationcomprises a full numbered multiple of the period length.

4. The grid, as set forth in claim 1, wherein the total graduationcomprises a nonfull numbered multiple of the period length.

5. The grid, as set forth in claim 1, wherein the total graduationcomprises a fraction of a full period extending over at least Pl )/2units and containing more than 2n/3 graduation characteristics.

6. A grid system comprising a first grid with graduation markings ofequal width relative to each other and succeeding one another innonequidistant spacings and a second grid photoelectrically or opticallycooperating scanningly with said first grid and adapted to produce asignal during their relative displacement,

said graduation markings defining centerlines,

said centerlines of such graduation markings following each other inspaced distances corresponding with a cycle of n graduation markings,and

said cycle having a period length of units and each full numberedmultiple of a unit occurring as spacing between any two of saidgraduation markings exactly k times, n and k being integral numbersatisfying the relationship n23 and ngl ,respectively.

1. A grid with graduation-markings of equal width relative to each otherand succeeding one another in nonequidistant spacings, saidgraduation-markings defining centerlines, said centerlines of suchgraduation-markings following each other in spaced distancescorresponding with a cycle of n graduation markings, and said cyclehaving a period length of units and each full numbered multiple of aunit occurring as spacing between any two of said graduation markingsexactly k times, n and k being integral numbers satisfying therelationship n 3 and 1 k (n-1)/2, respectively.
 2. The grid, as setforth in claim 1, wherein said individual graduation-markings compriseranges, contrasting relative to their surrounding, of a width at themost of one unit.
 3. The grid, as set forth in claim 1, wherein thetotal graduation comprises a full numbered multiple of the periodlength.
 4. The grid, as set forth in claim 1, wherein the totalgraduation comprises a nonfull numbered multiple of the period length.5. The grid, as set forth in claim 1, wherein the total graduationcomprises a fraction of a full period extending over at least P-1)/2units and containing more than 2n/3 graduation characteristics.
 6. Agrid system comprising a first grid with graduation markings of equalwidth relative to each other and succeeding one another innonequidistant spacings and a second grid photoelectrically or opticallycooperating scanningly with said first grid and adapted to produce asignal during their relative displacement, said graduation markingsdefining centerlines, said centerlines of such graduation markingsfollowing each other in spaced distances corresponding with a cycle of ngraduation markings, and said cycle having a period length of units andeach full numbered Multiple of a unit occurring as spacing between anytwo of said graduation markings exactly k times, n and k being integralnumber satisfying the relationship n 3 and l k (n-1)/2, respectively.